VetBadger does not support an automated way to merge clients, but it's possible to transfer patient ownership between clients 

if you have duplicated records. That process is described here: 
https://vetbadger.freshdesk.com/a/solutions/articles/6000236796

Once all of the patients are recorded under a single owner, it's possible to merge duplicate patient records using the link at the bottom of the "Patient Context Menu" (from the patient dashboard):



Once you have transferred all of the patients, now just mark the client as disabled.